Shale sludge distributor



J. L. HoTz Erm. 2,892,758

sHALE sLUnGE DISTRIBUTOR June 30, 1959 Filed May 14, 1956 2 sheets-sheet1 June 30, 1959 J. L.' HoTz ETAL sHALE sLUD GE DISTRIBUTOR Filed May 14.195e 2 Sheets-Sheet 2 lIll Illll United States Patent C) SHALE SLUDGEDISTRIBUTOR John L. Hotz and Robert L. Switzer, Long Beach, Calif.,vassignors to Union Oil Company of California, Los

Angeles, Calif., a corporation of California Application May 14, 1956,Serial No. 584,854

12 Claims. (Cl, 2412-6) This invention relates to improvements in solidsuid contacting and particularly to an improved process and apparatus forthe production of hydrocarbon gases and oils from solids by thermalmeans. Applicable solids include such oil-producing and oil-containingmaterials as oil shale, tar sand, oil-saturated diatomite, bituminousand sub-bituminous coals, and the like. The description will beconducted in terms of the eduction of shale oil and gas from oil shalefor the sake of simplicity and with the understanding that the processand apparatus are applicable in general to other solids from which oilsand gases can be produced, and to solids-fluid contacting processes ingeneral.

Some processes for the eduction of shale oils and gases involve thedownward passage of shale rock as a moving bed by gravity through avertical heat treating kiln. During this passage they are heated toeduction temperatures by direct or indirect means. From a thermalefciency standpoint the direct heating means is preferred in which acountercurrent contact of hot gases with the shale rock is employed. Toavoid the large fuel consumption otherwise required, most of theseprocesses involve the direct injection of air or other oxygen-containinggas into the bottom of the kiln to burn the carbonaceous residue fromthe spent shale. rl`his generates hot flue gases needed to heat therock. However, some difficulties are encountered with the fusion of thespent shale due to this burning, and frequently the fused or partiallyfused rock plugs the air inlet requiring a shutdown. Since all of thehydrocarbon product is removed at the top of the kiln, it

ymust be removed as a vapor and thus the process requires extensivecooling and condensing facilities.

Other shale eduction processes have successfully avoided the large fueland condensing water requirements by utilizing an upilow of shale rockand a downilow of heating gas. The shale is fed upwardly successivelythrough a perforated product fluid-shale rock disengaging section and aheat treating and kiln section. Air or other oxygen-containing gasenters the top of the heat treating section, is preheated in cooling thehot shale ash, burns the carbonaceous residue from the spent shale, andthe hotline gases continue downwardly to heat the shale rock to eductiontemperatures. The hydrocarbon oils and gases are thus evolved in theeduction zone. The whole vapor phase passes downwardly in direct contactwith the raw shale, and is cooled thereby condensing the hydrocarbon oiland preheating the raw shale. The liquid and gaseous products are drawnoff at the top of the disengaging section and are thus separated fromthe upwardly moving shale rock. A solids feeder passes the shale rockupwardly through the disengaging and heat treating sections anddisplaces the shale ash out the top of the unit. The process suppliesits own fuel in the form of carbonaceous spent shale. It cools andpartially condenses its own product in preheating the raw shale rock.

One principal problem of these processes involves the presence of solidslines in the solids to be thermally treated and in the presentillustration these nes are exemplied by shale fines in the feed. In thedownow solids processes, a screening step is required to separate fromthe rock fed to the process the shale nes whose average dimensions areless than about 0.25 inch. In the upow shale process, the problem isaggravated with screw feeders, and non-vertically acting piston feeders.With such solids feeders it has been found that the quantity of nes inthe feed increases as much as vor more when such solids feeders areemployed and that up to about 50% of the feed is reduced to nes. In thepresent invention a vertical reciprocating pistonfeeder, hereinaftermore fully described, is used. This piston feeder successfully passesshale rock upwardly through the apparatus of this invention without theformation of substantial quantities of additional nes. The process andapparatus are also capable of a substantially complete retorting ofvaluable products from those fines which naturally occur in theunscreened feed and thus they accomplish what all the previous retortingprocesses were incapable of accomplishing.

The present invention is therefore directed to an improved upow shaleretorting process as illustrative of those solids heat treatingprocesses in which the solids are passed upwardly countercurrent to adownflow of hea't treating fluid and in which process steps andapparatus elements are utilized to avoid the necessity of solids nesseparation from the feed and to obtain a complete and uniform heattreatment of all solids including the lines.

It is thus a primary object of this invention to pro-vide an improvedsolids-fluid contacting process.

It is an additional object to provide a particularly improved solidsupow and uid downflow heat treating process especially adapted to theproduction of hydrocarbon gases and oils from solids.

It is a more specific object of this invention to provide an improvedprocess for the retorting of shale including shale fines to effect asubstantially complete recovery of shale oil and gas from the shale rockincluding the shale fines.

lt is another object of this invention to collect fine solids fallingthrough the disengaging zone in which product uids are disengaged fromthe solids fed to the process, to return these lines to a specific pointin the shale hopper so that they may be drawn into the system and fedupwardly through the contacting zone at the center of the upwardlymoving mass of solids so as to minimize fallout of these recirculatedsolids. y

It is also an object of this invention to provide an apparatus adaptedto accomplish the aforementioned objects.

Other objects and advantages of this invention will become apparent tothose skilled in the art as the description thereof proceeds.

The present invention will be more readily understood by reference tothe accompanying drawings in which:

Figure 1 is a side elevation view in partial cross section of theimproved apparatus of this invention shown in conjunction with aschematic flow diagram of the process,

Figure 2 is a side elevation view of the detail of the nes distributorlocated in the feed hopper,

Figure 3 is an end view of the distributor,

Figure 4 is a plan view looking downwardly into the feed hopper, and

Figure 5 is a partial elevation view taken at right angles to theapparatus shown in Figure 1.

Referring now more particularly to Figure l, the process of the presentinvention will be described in terms of a specific example of thepresent invention as applied to the retorting of oil shale to produceshale oil and shale gas. The apparatus of the present invention consistsessentially of three parts; namely an upper heat treating or eductionkiln 10, an intermediate solids-fluid feeding position shown and aninclined cylinder charging position not shown but in which the upperoutlet opening of cylinder 18 is disposed to the left and immediatelybelow the lower outlet opening of shale feed hopper 2t). `A hydraulicactuating cylinder 22 disposed within cylinder-1 8 reciprocates feederpiston 16 in cylinder 18. A lsecond hydraulic cylinder 24 containedwithin feeder Vcase 14 oscillates feeder cylinder 18 between the llingand feeding positions. A V-shaped trough 1S runs along the bottom of thecase and has a screw conveyor 17 at its apex to move settled finestoward outlet 19. A stream of oil is introduced into case 14 throughline 23 controlled by valve 25 and serves to flush the lines slurry fromthe outlet 19 through line 27. This slurry is re- 'turned to theintegral settling chamber by pump 29 and line 31 to recycle finesthrough seal or distributor 90 to a point in the settler which is belowliquid level Si).

Raw shale is introduced by any convenient conveyor means not shown inthe direction indicated into feed hopper 20 around fines distributor 90.With feeder pistonY 16 disposed at its upper extremity immediately afterits upstroke, cylinder 18 is moved to a point in alignment with feedhopper 20 by hydraulic cylinder 24. Cylinder 22 retracts piston 16drawing a charge of shale rock and any recycled fines into the upperpart of feeder cylinder 18. Hydraulic cylinder 24 is then extendedreturning feeder cylinder 18 to the vertical position shown. Thenhydraulic cylinder 22 is extended forcing piston 16 upwardly therebymoving the charge of rock into disengaging section l2 and displacing therock therein and in kiln y upwardly. This cycle is repeated therebycontinuously feeding fresh shale at the bottom of the structure anddisplacing cool shale ash from the top.

The shale ash is displaced as described from the top of kiln 10 andinside housing 26. It falls by gravity through the paths indicated as byarrows 28 and 30 downwardly on to the bottom 30 of housing 26 anddischarges through outlet 32 into ash disposal conveyor 34.

KilnV 10 is provided with a plurality of radial fins 36 disposed on itsoutside surface. Jacket 35 surrounds the outer edges of the tinsproviding a series of adjacent nearvertical Ypaths for cooling air whichpasses by natural or forced convection upwardly within jacket 38, intomanifold 40, and then out through stack 42 to the atmosphere. Ifdesired, this warm air may at least in part be introduced into the topof the kiln through line 44 together with other gases subsequentlydescribed.

The raw shale is passed by means described above upwardly through gasand liquid disengaging section l2 in which the cool flue and shale gasesand the condensed shale oil are disengaged from the upwardly moving massof shale. In kiln 10 the upwardly moving shale passes successivelythrough a fresh shale preheating and product cooling and condensingzone, a shale eduction zone, a spent shale combustion zone, and a shaleash cooling and gas preheating zone. At this point the ashes areexpelled as described from the top of kiln 10. In order to support thecarbonaceous spent shale combustion, an oxygen-containing gas such asair is introduced through line 44 at a rate controlled by valve 46. Withthis gas may be mixed steam or water or a portion of the cool mixture ofshale and ue gas produced from the product separator 58. This gas passesdownwardly through the aforementioned zones in the reverse order. In theuppermost or shale ash cooling zone this gas is preheated by directcontact with the shale ash thereby cooling the ash to approximatelyatmospheric temperature. The preheatedgas then moves downwardly throughthe spent shale combustion zone in which hot ue gases aregenerated andthe carbonaceous shale is burned forming the shale ash. In the nextlower or eduction zone the hot flue gases contact and educt shale oiland gases from preheated fresh shale forming the spent carbonaceousshale and a vapor mixture of shale oil and gas together with the fluegas. ln the next lower zone, the fresh shale is preheated by directcontact with the products of eduction thereby cooling and partiallycondensing them forming a liquid oil phase and the preheated freshshale. The now cool gas phase continues downwardly and the liquidproduct runs downwardly by gravity lling the lower portion ofdisengaging section 12 approximately to level 5G at the lowerextremities of slots 52 which extend around the upper periphery ofdisengaging section 12. This liquid product lls feeder case 14 andstands up to level 50' in shale feed hopper 20 sealing it against entryof air. The difference between these levels 50 and 50 corresponds to thepressure differential existing by virtue of gas ilow through the shalerock bed in the apparatus. In other words, the apparatus is operatedunder a partial vacuum created by exhaust blower 52.

By means of blower 52 the cool product gases pass from the upwardlymoving shale bed through slots 52 into effluent manifold 54 surroundingthe disengaging section and therefrom directly into integrally attachedproduct vapor liquid separator and fines settler 58. Herein the gasesare separated from the condensed oil. The gas phase containing smallquantities of separated oil and unagglomerated mists, flows fromseparator S8 under the influence of blower 52 through line 60 at a ratecontrolled by valve 64 and differential pressure recorder controller 66into a centrifugal separator 68. From this separator the agglomeratedoil phase is removed through line 71 and combined with the liquidproduct produced through line 62 or pumped into settler 58. Theremaining gas phase llows under the pressure exerted by blower 52through line 70 into any sort of nal separator 72. This latter separatormay comprise an oil wash such as in an absorber, an electrostatic orultrasonic treatment, or any liquid scrubber, to clean up any residualdusts and oil mists, or other suitable separators. Oil recovered isremoved through line 73. Through line 74 the oil-free gas is dischargedto the atmosphere, or recirculated in part to the kiln as previouslydescribed.

The oil phase overflowing from disengaging section 12 through slots 52flows through manifold 54 directly into the integrally attached settler58, and in a serpentine path around bales 56. The oil temperature isabout F. and suicient settling time is provided to permit gravitation ofall solids fines larger than l0() microns. These solids are collected inscrew conveyors 84, 82 (directly behind 84), and 86 and are returned inthe manner described below to hopper 20. Settler 58 is provided withoverflow weir box 57 and weir 59 into which the product oil flows. It ispumped therefrom through line 60 by pump 64 at a rate suflicient tosupply all oil recycle Streams through line 65, such as that to feedercase 14, and produce a net oil product through line 62 at a ratecontrolled by valve 66 and liquid level controller 68.

A small quantity of shale nes is invariably present in the raw shale fedto the unit. Further, a small quantity of additional fines isunavoidably formed during the feeding of shale upwardly into theapparatus. For the most part these lines in the present apparatus passupwardly together with the oil-wet shale rock successively throughdisengaging zone 12 into retort 10 wherein the shale lines are retortedalong with the larger shale particles. However a minor portion of thefines associated with the upwardly moving bed of rock nearest theperiphery of the bed discharge at least in part with the oil and gasthrough slots 52 into eflluent manifold 54. This quantity of fines soentering manifold 54 is only a small proportion of the lines introducedupwardly from feeder case 14 with the upwardly moving mass of rock. i

yIn the present apparatus the shape of manifold 54 and theseparator-settler vessel S8 surrounding the perforated disengagingsection 12 is especially designed to provide for `the natural gravitysettling of these lines downwardly through the body of oil containedtherein so as to accumulate in a pair of horizontal parallel primaryfeeder screws 82 and 84 and a secondary or collection screw 86. Theseparatorsettler vessel bottom is W-shaped as shown in Figure 5 andconsists of a pair of adjacent V-Shaped troughs with the primary feederscrews 82 and 84 disposed horizontally along the bottom or apex of eachtrough. These troughs are closed at .each end and the disengagingsection 12 which is conical in form passes upwardly through the adjacentrconnecting sides of these troughs. Thus the nes which fall through theslots in one side of disengaging section 12 settle in one trough and thefines falling from the other side settle in the other trough. By gravitythey progress toward the primary screws 82 and 84 and are moved therebyin the same direction to a collection or secondary screw 86 disposed atright angles to the primary troughs at a point Vadjacent and above feedhopper 20. Fines falling through slots 52 above the hopper fall directlyinto the secondary screw conveyor 86. The slurry of shale finesdischarges from the end of each primary feeder screw 82 and 84 into theoutside ends of the collection screw 86. The collection screw 86consists of approximately equal len-gths of right-hand and left-handscrews disposed on a common shaft so that rotation of the shaft in theproper direction brings each of these slurries discharged from theprimary screw feeders toward a central point along the length of the`collection screw. This slurry at this point drops by gravity throughdistributor 90 directly into the feeder trough 20. Distributor 90 issealed against inflow of -air by means of liquid level 50. The raw shalemoves into hopper 20 around distributor and is fed as previous- -lydescribed upwardly with the recirculated fines through the apparatus bymeans of the oscillating reciprocating piston feeder.

The recycle nes distributor is indicated generally as at 90 in shalehopper 20. Beside effecting a partial separationof the nes entering withthe raw shale feed, the distributor is also connected in fines-receivingrelation to collection screw 86. It serves to concentrate both the freshand recycled lines at a specific center part in the cross section of thefeed hopper which is aligned with the longitudinal axis of the feederpiston when it is in the inclined charging position below the hopper.This center part is surrounded by the larger shale particles so that theshale charge drawn into the feed cylinder from the hopper consists of amass of shale particles surrounding the solids fines which areconcentrated near the center of the charge. As the feeder cylinderoscillates back to the vertical feeding position, additional largelshale particles fill any void space at the top of the charge which isnot filled by fresh and recirculated fines. This additional shale ilowsinto the feed cylinder from points between distributor 90 and theinboard or right-hand part designated 91 of hopper 20 as shown inFigure 1. In this way the feed cylinder is always full regardless of therate of recycle of shale fines. 1n addition those fines which areconcentrated from the fresh feed and which are recycled are located atthe center of the charge so as to pass upwardly through perforatedisengaging section 12 thereby eliminating any fall-through of therecycled lines and `reducing the fallvthrough from that which formerlyoccurred without distributor 90. This reduction results from the partialclassification of lines as the fresh freed passes over the distributor.

yIn, Figures 2, 3 and 4 are shown various detail views of thedistributor indicated generally at 90 in Figure l.

4Referring particularly to Figure 2 -a section of the rtop part offeeder case 14, part of disengaging section 12, and part of feed hopper20 are shown =as viewed along the axis of collection screw 86 in thesame direction as in Figure l. Vertically disposed in hopper 20 is aflat dividing and supporting plate 92 having a sloping leading edge 94and extends from an integral attachment 96'to the outboard edge of thecase of collection screw 86 outwardly to the inboard edge 98 of hopper20 effectively dividing it into two halves substantially along itsdiameter. A plurality of -triangularshaped bars 100 are integrallyattached at their inboard edges to dividing plate 92 and extendoutwardly and downwardly forming a grizzly. The spacing of theseparallel bars is preferably of the order of 1/2 inch, or the approximatedimension of the largest sized particle which is considered to be a tineparticle in the process being carried out.

The upper extremities 102 of these bars parallel the upper or leadingedge 94 of dividing plate 92. The lower ends 104 however are disposedalong a line having a relatively steep slope yand substantially parallelwith chute 106 extending downwardly from outlet opening 108 ofcollection screw 86. In this way an open lines return channel 110 isprovided below the lower extremity of grizzly bars 104, above recyclechute 106, and between the side plates 112 and 114 (not shown) of thedistributor. The lower end of chute 106 is provided with an angularinboard end piece 11S. An angular outboard end piece 116 is alsoprovided which encloses a fines reservoir 118 at the lower extremity ofnes return channel 110.

In this structure therefore the raw shale fed in the direction indicatedpasses downwardly across leading edge 94 and then downwardly andoutwardly across the upper surface of grizzly bars 100 therebypreventing entry of the large shale particles into fines reservoir 118.Most of the nes solids present in the feed pass between bars 110directly into fines reservoir 119 to join those collected as indicatedin connection with Figure 1 and discharged through outlet 108 ofcollection screw 86 through return channel 110. Outboard end piece 116prevents the fines from collecting at the lower or outboard edge of themass of shale present in feed hopper 20 and maintains the finessubstantially at the center of the feeder piston when the piston is inthe cylinder charging position.

Referring briefly to Figure 3, an end view of the distributor in Figure2 is shown, showing supporting or dividing plate 92, the various grizzlybars 100 showing the slope of their upper surfaces, and lines reservoir118 located between side plates 112 and 114.

Referring to Figure 4 a plan View of the distributor looking downwardlyalong the axis of the feeder cylinder in the charging position is shown.Again dividing plate 92 is shown extending from the inboard edge 98 offeed hopper 20 to the outboard edge 96 of the collection screw case 86.Disposed on either side of dividing plate 92 are shown bars 100 havingspaces 101 therebetween and which fresh fines can enter fines recyclereservoir 118. The location of the reservoir between inboard andoutboard angular end plates and 116 and between side plates 112 and 114is shown. It is apparent in Figure 4 in which the raw shale from feedhopper 20 passes downwardly around the distributor that reservoir 118 iskept free of large shale particles being deflected outwardly in bothdirections by upper surfaces of bars 100. The outlet opening 108 ofcollection screw 86 is shown in broken lines opening downwardly intolines recycle channel 110. In this way both the recycle fines and asubstantial part of the fresh fines are concentrated in centrallylocated reservoir 118. They are passed by means of the feeder cylinderand piston, shown in Figure l, upwardly through the center of the risingshale mass.

In Figure 2 chute 106 is shown spaced apart from the Wall of disengagingsection 12 providing an open space 111. As will be apparent in Figure 4,this open space exists on the inboard side of inboard angle end plate115 and below chute 106. Entering raw shale substantially tills space111 by passing downwardly around the inboard grizzly bars. If then thequantity of fines recycle is insufficient to fill that portion of thefeeder cylinder disposed immediately below lower outlet opening 120 ofreservoir 118, this space is filled with large solids flowing from space111 as the mouth of the feeder cylinder passes that point on its way tothe vertical feeding position. Thus the feeder cylinder is always fulland the fines recycled are always disposed at the center of the chargeto the apparatus.

Referring finally to Figure 5, the W-shaped bottom of theseparator-settler vessel 58 referred to previously is shown. The otherelements shown are identified by the same numbers as in Figure l and hasdescribed above in connection with that ligure.

The apparatus of the present invention employed a feeder piston 5.5 feetin diameter and the rated shale capacity was 350 tons per day. Thedisengaging section 12 was 8 feet high having a lower diameter of 5.5feet and an upper diameter of l feet. The kiln section it) was 12 feethigh, with diameters of l5 feet at the bottom and 18 feet at the top.The combined eiuent manifold 54 and separator-settler vessel 5Saccording to this invention in this installation was constructedsubstantially as shown in Figure 2 and was provided with two V-shapedtroughs coinciding at their nearest edges and closed at their extremeends. An area of 70 square feet for fines settling was provided and nofines larger than 120 microns appeared in the oil product. The settlerwas provided along the lower apexes with two primary screws which wereinches in diameter and 20 feet long. These screws turned atapproximately 5 r.p.m. discharging shale fines slurry into a collectionscrew feeder of the same diameter and 10 feet long turning at 5 rpm. Thescrew conveyor in feeder case 14 was 6 inches in diameter and 15 feetlong and turned at 5 r.p.rn. The fines slurry was successfully returnedat a rate corresponding to about 5% of the rate at which the apparatusprocessed shale.

The dividing plate in the distributor was 3.5 feet high measuringangularly along the axis of the feeder piston in the filling position,and was 5 feet wide between col lection screw case and the outboard partof the hopper. The dividing plate was provided with 16 triangularshapedbars to form a grizzly, the bars being 2 inches thick and spaced on 2.75inch centers. The nes reservoir thus formed was 1.25 feet wide and 3.50feet long. The installation of the distributor resulted in a substantialdecrease of fines recycle due to the location of recycled fines in thecenter of the charge and the inclusion of a part of the nes present inthe feed in this centrally located concentration of fines. The operationwas completely successful.

It is important in the construction of this apparatus to maintain thedownward slope of the sides and of the end closures of the W-shaped andV-shaped troughs in the separator-settler and feeder case sufcientlyhigh so as to eliminate completely the possibility of nes settling andhanging upon these surfaces. To insure that the lines so contactingthese surfaces will slide downwardly toward the primary screws, thesesurfaces should describe an angle with respect to a horizontal plane ofat least 45 degrees and preferably above about 55 degrees. Anglesgreater than about 8O degrees however are unnecessary and will onlyunduly increase the height of the apparatus.

Again it should be emphasized that although the foregoing detaileddescription has been conducted in terms of the production of shale oiland gas from oil shale, the present process and apparatus is clearlyapplicable to other solids-fluid contacting processes in which a liquidproduct is produced during a reaction or contact between moving solidsand a fluid and in which solids fines must be thoroughly treated. Asstated above, the process is applicable with advantage to the treatmentof such solids as oil shale, tar sand, bituminous and sub-bituminouscoals, bitumen-saturated diatomite or other solids.

A particular embodiment of the present invention has been hereinabovedescribed in considerable detail by way of illustration. It should beunderstood that various other modifications and adaptations thereof maybe made by those skilled in this particular art without departing fromthe spirit and scope of this invention as set forth in the appendedclaims.

We claim:

1. A method for solids-uid contacting to produce a liquid product whichcomprises passing solids as a dense mass downwardly through a hopperzone into a vertically acting feeder zone, passing said solids therefromas a dense mass upwardly successively through a foraminate disengagingzone and a contacting zone, passing a uid `downwardly through saidcontacting zone and said disengaging zone into a communicatingseparator-settler zone, removing gases and liquids separately from saidseparator-settler zone, removing settled solids lines from the bottom ofsaid separator-settler zone, and introducing substantially all of saidlines into said hopper zone at a low central point therein so that saidfines are surrounded by fresh solids and are passed upwardly sosurrounded from said feeder zone through said disengaging and contactingzones thereby minimizing fallout of said fines from said disengagingzone into said separator-settler zone.

2. A method according to claim 1 in combination with a foraminate solidsfines distributor-classifier zone centrally disposed in said hopper zoneand into which said settled solids are recycled and around which saidfresh solids are introduced whereby solids fines associated with saidfresh solids are at least partly accumulated in saiddistributor-classifier zone in admixture with said settled solids nesintroduced therein from said separator-settler zone.

3. A method according to claim 1 in combination with the step ofcollecting settled solids nes in said feeder zone, pumping a liquidproduct stream therethrough to form a fines and recycling a slurry ofsaid ines pumped `from said feeder zone to said hopper zone at a lowcentral point therein.

4. A method according to claim 1 wherein said solids are crushed oilshale, said fluid introduced into said contacting zone is anoxygen-containing gas, and said liquid product comprises shale oil.

5. A method for producing shale oil and gas from crushed oil shale whichcomprises passing crushed oil shale as a dense mass downwardly above andaround a foraminate shale nes classifier-distributor zone disposedcentrally in a hopper zone, drawing shale from said hopper zonedownwardly into a vertically acting shale feeder zone, displacing theshale upwardly from said feeder zone successively through a foraminatefluid-solids disengaging zone surrounded by a closed separator-settlerzone, and through a shale retorting zone, passing eduction gasesdownwardly through said retorting zone at shale oil and gas eductiontemperatures and into and from said disengagmg zone into saidseparator-settler zone, separately removing shale oil and gasestherefrom, collecting a slurry of settled oil shale iines at the bottomof said separatorsettler zone, and introducing substantially all of said-slurry into said foraminate fines distributor-classifier zone intoadmixture therein with shale fines separated there from said crushed oilshale passing downwardly around 1t 1n said hopper zone, whereby saidfines are concentrated near the ycenter of the oil shale charge in saidfeeder zone and are passed upwardly so centered in the mass of oil shalethrough said disengaging and retorting zones.

6. A method according to claim 5 in combination with the step ofmaintaining a shale oil level in said hopper zone which submerges atleast the lower part of said distributor-classifier zone so as to sealit against now of air.

7. In an apparatus for Huid-solids contacting comprising a contactingvessel, a foraminate disengaging vessel, and a vertically acting solidsfeeder case disposed at successively lower levels in a column, aninclined solids inlet hopper opening downwardly at an angle into the topof said feeder case adjacent the connection thereto of said disengagingvessel, an oscillating, vertically-acting piston solids feeder disposedwithin said feeder case, means for oscillating and reciprocating saidpiston so as to receive a charge of solids as a mass from said hopperand force said mass upwardly through said disengaging and contactingvessels, a closed separator-settler vessel surrounding said disengagingvessel, and means for removing at least one uid stream therefrom, theimprovement which comprises in combination therewith a solidsdistributor-classier centrally disposed in said hopper and open at itslower end, closed at its sides and at its outboard and inboard ends, andmeans for removing settled fines from the bottom of saidseparator-settler and charging them into the inboard end of saiddistributor-classifier so as to `centralize the mass of recycled solidsfines in said mass of solids entering said feeder and in said masspassed upwardly through said column.

8. An apparatus according to claim 7 wherein saiddistributor-classii'ier is provided with a plurality of parallel barsspaced apart from one another forming the upper end thereof wherebyfines in said mass of solids passing through said hopper pass betweensaid bars directly into said distributor and the larger solids arediverted downwardly around said distributor into said feeder as a masscontaining a centralized concentration of fresh classified and recycledsolids fines.

9. A11 apparatus according to claim 8 wherein the upper edges of saidparallel bars slope downwardly away one each side from a central highpoint forming an inverted V-shaped ridge to divert solids around saiddistributorclassier.

10. An apparatus according to claim 7 wherein said means for removingsettled iines comprises at least one screw conveyor disposed at thebottom of said separatorsettler and which opens directly into theinboard end of said distributor-classifier.

11. An apparatus according to claim 7 in combination with a screwconveyor disposed along the bottom of said feeder case, means forpumping a stream of liquid from adjacent the liquid outlet end of saidseparator-settler into said feeder case, and means for pumping a slurryof liquid and collected lines from the outlet end of said screw conveyorin said feeder case to the opposite end of said separator-settler so asto return fines solids from said feeder case to said hopper.

12. In an apparatus for solids-huid contacting comprising a closedsolids feeder case, a foraminate disengaging section surrounded by aclosed separator-settler vessel disposed above said case, a contactingvessel disposed above said disengaging section, a generally cylindricalhopper' opening angularly downward into said case beside saiddisengaging section, and an oscillating feeder cylinder having areciprocating piston therein disposed Within said case adapted toreceive solids from said hopper and force them upwardly successivelythrough said disengaging section and said contacting vessel, theirnprovement which comprises a substantially vertical plate disposed insaid hopper and aligned with the vertical axis of said disengagingsection, a plurality of parallel plates spaced apart from one anotherdisposed perpendicular to and on both sides of said plate and whoseupper edges slope outwardly therefrom, a pair of side plates integrallyattached to the outer extremes of said first-named plates and formingwith angular end members an enclosure below said iirst-named plate whichis generally centrally located within and at the bottom of said hopper,whereby solids entering said hopper surround said enclosure, and meanscommunicating said enclosure with means for collecting settlednes solidsin said separator-settler.

References Cited in the file of this patent UNITED STATES PATENTS2,501,153 Berg Mar. 2l, 1950 2,640,014 Berg May 26, 1953 2,640,019 BergMay 26, 1953

1. A METHOD FOR SOLIDS-FLUID CONTACTING TO PRODUCE A LIQUID PRODUCTWHICH COMPRISES PASSING SOLIDS AS A DENSE MASS DOWNWARDLY THROUGH AHOPPER ZONE INTO A VERTICALLY ACTIGN FEEDER ZONE, PASIG SAID SOLIDSTHEREFROM AS A DENSE MASS UPWARDLY SUCCESSIVELY THROUGH A FORMINATEDISENGAGING ZONE AND A CONTACTING ZONE, PASSING A FLUID DSOWNWARDLYTHROUGH SAID CONTACTING ZONE AND SAID DISENGAGING ZONE INTO ACOMMUNICASTING SEPARATOR-SETTLER ZONE, REMOVING GASES AND LIQUIDSSEPARATELY FROM SAID SEPARATOR-SELLTER ZONE, REMOVING SETTLED SOLIDSFINES FROM THE BOTTOM OF SAID SEPARATOR-SETTLER ZONE, AND INTRODUCINGSUBSTANTIALLY ALL OF SAID FINES INTO SAID HOPPER ZONE AT A LOW CENTRALPOINT THEREIN SO THAT SAID FINES ARE SURROUNDED BY FRESH SOLIDS AND AREPASSED UPWARDLY SO SURROUNDED FROM SAID FEEDER ZONE THROUGH SAIDDISENGAGING AND CONTACTING ZONES THEREBY MINIMIZING FALLOUT OF SAIDFINES FROM SAID DISENGAGING ZONE INTO SAID SEPARATOR-SETTLER ZONE.